Bulletin d’avalanche

Purcells

Apr 19 – 20, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Sun
Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–4
    Wind slabs exist on a variety of aspects at treeline and above. Cornices have grown very large, so be aware of overhead hazards and stay back on ridgelines.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1–6
    A weak interface buried in the upper metre of the snowpack can create surprisingly large avalanches. It's been reactive in nearby regions, and remains a concern with professionals. Be cautious in steep, alpine terrain.

Confidence

Fair - Due to limited field observations

Weather Forecast

An upper trough will move through the Interior tomorrow, while the NW flow will bring cooler, dryer air and decent pulses of precipitation.Saturday: Overcast. Light-moderate precipitation amounts. Ridgetop winds blowing moderate from the NW. Freezing levels near 1600 m.Sunday/Monday: A ridge of high pressure will bring a mix of sun and cloud, with cooling and dryer conditions. Freezing levels will be near 1000 m during the afternoon and falling to valley bottom overnight.

Avalanche Summary

No new avalanche activity has been reported.

Snowpack Summary

Up to 10 cm of new snow overlies a variety of old snow surfaces. These consist of melt-freeze crusts, buried surface hoar and surface facets. Touchy wind slabs exist on lee slopes and behind terrain features. Cornices on ridgelines have grown large, and pose a threat to slopes below.Deeper in the snowpack a weak interface buried in early April is down about 60-120 cm and consists of a crust on solar aspects, and surface hoar on high-elevation northerly aspects. Earlier this week, very large avalanches were reactive on this interface in the neighboring Glacier National Park. The bond may be getting stronger, but I would still use caution and be suspicious of large, steep upper elevation slopes.

Régions couvertes